The present invention relates to a tape position data recording method for recording tape position data on a video tape.
In the case where a number of programs have been recorded on a video tape by a video tape recorder (VTR), it is considerably difficult to locate the start of a desired one among the programs.
Heretofore, program search operation have been carried out according to the following three methods:
In accordance with the first method, a blank region is provided between the end of each recorded program and the start of the following recorded program, and the tops of programs are located by detecting the blank regions. In order to specify a program the top of which should be detected, it is necessary to detect the current position in a present program and to externally input the position of the desired program measured therefrom. Therefore, the first method is disadvantageous in that the operation of the VTR is so intricate that the VTR is liable to be operated erroneously, and it is difficult to automatically search among a large number of programs.
In accordance with the second method, cue signals for locating the tops of programs are recorded in a cue track provided along one edge of the tape, or times (hours, minutes and seconds) corresponding to tape lengths from the start end of the tape are recorded successively therein, so that, in the cue search mode, these signals are read to detect the top of a desired program. Detecting the top of a program by using the cue signal only is substantially equivalent to the above-described first method of signal processing, and recording and reading out of these times (hours, minutes and seconds) is not applicable to consumer applications because of its complexity.
In accordance with the third method, VITCs (Vertical Interval Time Codes) are recorded in correspondence to video tracks on the video tape, and the VITC corresponding to the end of a program is specified in a program search operation. The third method is advantageous in that the top of a program can be automatically located, and the top of a number of programs can be detected automatically and successively. However, the third method is still disadvantageous in that, in a video tape recorder, the number of tracks recorded is generally sixty per second in the NTSC system, and accordingly a one-hour recording tape has 216,000 tracks. It is necessary to record an equal number of VITCs in the tracks, and it is necessary for the user to note or remember the count values which are provided in correspondence to the VITCs of the tops of recorded programs. Therefore, such a VTR system may be suitable for professional use but not for consumer use.